Erosion is a major problem on aircraft, especially for the leading edges of the airfoil elements. The protective systems known for these zones are divided into two types:
Metallic coatings: caps made of titanium, steel or other metal alloys of Ni/Co type have a good resistance to rain erosion, but are rapidly eroded by sand.
Highly ductile organic coatings, in the form of adhesive films based on essentially polyurethane elastomer, have a good resistance to sand erosion but their durability remains rather unsatisfactory. These films are used, on the one hand, as temporary protection on the metal cap of blades for helicopters subjected to sand erosion and, on the other hand, as longer-lasting protection in the vicinity of the blade root. When they are not used near the root, they do not however withstand rain conditions.
In particular, it turns out that if an aircraft equipped with films for protection against sand erosion passes through a storm, these films are completely deteriorated in around 15 minutes.
The main problem is therefore the absence of an effective solution for protection against sand erosion that is capable of sufficiently withstanding rain erosion in order not to be changed too often, yet more and more users are requesting to be able to fly over all terrains and in all weather conditions.
Protection that combines resistance to sand erosion and rain erosion would in particular enable military vehicles to be suitable for missions in demanding environments and in particular that combine the problems of desert and tropical environments.